multithreading - Posix thread Program Multiplication - Inquire about Code blog How to check that it issues different threads -

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found in below link blog showing example on matrix multiplication using posix thread, , mentioned each threads holding row , column information, below link , copied program reference

https://macboypro.wordpress.com/2009/05/20/matrix-multiplication-in-c-using-pthreads-on-linux/

#include <pthread.h> #include <stdio.h> #include <stdlib.h>  #define m 3 #define k 2 #define n 3 #define num_threads 10  int [m][k] = { {1,4}, {2,5}, {3,6} }; int b [k][n] = { {8,7,6}, {5,4,3} }; int c [m][n];  struct v {    int i; /* row */    int j; /* column */ };  void *runner(void *param); /* thread */  int main(int argc, char *argv[]) {     int i,j, count = 0;     for(i = 0; < m; i++) {       for(j = 0; j < n; j++) {      //assign row , column each thread      struct v *data = (struct v *) malloc(sizeof(struct v));      data->i = i;      data->j = j;      /* create thread passing data parameter */      pthread_t tid;       //thread id      pthread_attr_t attr; //set of thread attributes      //get default attributes      pthread_attr_init(&attr);      //create thread      pthread_create(&tid,&attr,runner,data);      //make sure parent waits thread complete      pthread_join(tid, null);      count++;      }   }     //print out resulting matrix   for(i = 0; < m; i++) {      for(j = 0; j < n; j++) {      printf("%d ", c[i][j]);     }     printf("\n");    }  }  //the thread begin control in function void *runner(void *param) {    struct v *data = param; // structure holds our data    int n, sum = 0; //the counter , sum     //row multiplied column    for(n = 0; n< k; n++){        sum += a[data->i][n] * b[n][data->j];    }    //assign sum coordinate    c[data->i][data->j] = sum;     //exit thread    pthread_exit(0);  }

inquiry : issuing different threads each different row/column ? , how can define different threads issued ?


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